ATC recording captures bizarre moment man in jetpack flies past American Airlines flight arriving in Los Angeles.

Pilots get to see a lot of interesting things during their workday, but what these pilots saw out the window of their cockpit on Sunday (local time) was certainly a first.

On approach to the busy Los Angeles Airport (LAX), the pilot of American Airlines 1997 spotted a man flying in a jetpack dangerously nearby.

The bizarre incident played out over air traffic control, with staff on the ground and in the air puzzled by what had been seen.

"Tower, American 1997, we just passed a guy on a jetpack," the American Airlines pilot said to controllers.

"Off the left side, maybe 300 yards (270m) or so, about our altitude."

The captain of another flight confirmed the sighting moments later.

"Tower, Skywest, we just saw the guy passing by us in the jetpack."

Other aircraft were then warned of the unusual danger within the vicinity of the airport. One pilot sounded just as excited by the presence of a man in a jetpack as he was alert.

"We heard and we are definitely looking."

The airspace around LAX is heavily restricted due to its size and frequency of arrivals and departures, and special clearance needs to be requested when flying anywhere near it.

The incident - which is under investigation - was perhaps summed up best by the last pilot transmission regarding the mystery jetpack.

 "Only in LA."